The present invention applies to flight management systems for aircraft with or without a pilot on board. Such systems provide pilot assistance functions for determining the route to be followed by the aircraft to home in on its destination from its departure point taking into account the regulatory and operational constraints to be observed.
These constraints include the procedures to be employed in given emergencies as prescribed by international organizations, state and airport authorities. In particular, such cases include aircraft hijacking, medical emergencies, malfunctions affecting the aircraft's flight qualities (engine, pressurization, etc.), communication failures, making ground/air or air/air dialogue, and accordingly control of the aircraft in question impossible. According to Eurocontrol, the body responsible for controlling European airspace, such communication failures (Prolonged Loss of Communication or PLOC) involved over 1000 flights between 1999 and 2005. These failures increase the risk of collision and have a significant cost since they must be taken into account in air traffic control design to enable traffic reorganization when they occur. In the extreme, these failures mean forcing the airplane to the ground by fighter planes.
The procedures to be employed in these emergencies depend on the location of the aircraft, which determines the applicable regulations. They are therefore voluminous and complex. Furthermore, they do not prescribe any single solution that can be directly integrated into a flight management system since a choice must be made from an infinite number of options. This explains why in the present state of the art there is no solution for automatically or semi-automatically taking these procedures into account in a flight management system. This is a significant drawback for aircraft with a pilot on board, since there is a heightened risk of misapplication of complex procedures by the crew and potential breaches of security are greater. It is a completely unacceptable drawback for military aircraft whose pilot is not on board, known as drones. These may be authorized to fly in non-segregated airspace, i.e. shared by civil aircraft, only if they are able to apply the same regulations and procedures, particularly in the event of an emergency situation. But currently this cannot be ensured for a drone, particularly in the event of a communication failure. In fact, if it is the control link that is interrupted, the extreme solution of instructions visually communicated by fighter planes is not applicable; if it is the link between the drone and its pilot that is interrupted, the latter cannot give any instruction to the aircraft. The solution to the problem consisting in automatically or semi-automatically taking account of procedures to be applied in emergency situations in a flight management system is therefore particularly critical.